We propose to use our fluorescence and other spectroscopic apparatus and our relevant theoretical competence as physical chemists to investigate human and animal eye lenses. The experimental methods are chosen so as to be non destructive and therefore applicable to living animals as well as to intact, enucleated lenses and lens protein fractions. The objectives are to document spectroscopic differences between normal and cataractous human lenses in vitro, to interpret these data at the molecular level, to spectroscopically characterize animal lenses in vivo and study any eye damage produced by ultraviolet and visible light sources, and to determine whether in vivo spectroscopy of human lenses will be safe and useful for early detection of cataracts. We will be aided in this project by several ophthalmological consultants from neighboring institutions.